Malfunction Codes
Accessing the ECM
The ECM is located in the passenger side footwell. You need to remove 2 rivet type fasteners of the right doorstep in order to get the kick panel out. To remove these, unscrew the center part and pull up on the other part. Two metal screws and another rivet type fastener hold the kick panel to the body of the car. Under the panel, is the ECM with its connector. Remove the two screws at the top and bottom of the ECM and gently turn it to get to the Model Selector and RED L.E.D. Don’t unplug the ECM to do this! There should be a small sticker by the Mode Selector that tells you to turn it clockwise to set the Modes, and to be sure to return it all the way counter-clockwise to the original position when the car is in use. You will also see the RED L.E.D. inside the ECM.
Diagnostics Modes
There are two modes and two conditions for the engine to be in for running diagnostics. All modes are with the Ignition Switch in the ON position.
* Mode I (Engine OFF)- Bulb Check
* Mode I (Engine ON) – Malfunction Warning
* Mode II (Engine OFF)- Stored Self Diagnostic Results
* Mode II (Engine ON)- Exhaust Gas Sensor Monitor
Note: The ECM will automatically return to Mode I when the ignition is switched OFF. When the ECM is changed from Mode II back to Mode I by using the Mode Selector, the malfunction code(s) stored for Mode II will be erased.
Changing Modes
Switching modes is not possbile while the engine is running.
* Turn the Ignition switch ON
* The ECM is now in Mode I
* To switch to mode II:
o Turn the ECM Mode Selector fully CLOCKWISE, hold for at least 2-seconds and then return the Mode Selector to it’s original position. You are now in Mode II.
o (Notes: Return to Mode I by turning the Mode Selector fully CLOCKWISE again, holding for another 2-seconds and turning it back to the original position. Doing this will ERASE any Malfunction Codes that are stored in the ECM for Mode II.)
Reading the Malfunction Codes:
The malfunction modes are indicated by the number of flashes by the RED L.E.D. and the check engine light, you can read either of them, as they both display the same thing. Example: if the red LED flashes once and after a short pause flashes twice, this resembles the number “12″.
Please Note: The following chart was derrived from a 240sx service manual. Your car may be different, so please consult your manual for your car.
Code: Item:
11 Cam Position
12 MAF
13 Coolant Temp
14 Vehicle Speed
21 Primary Ingition signal
25 IACV
31 ECM
32 EGR
33 Primary O2 (fron)
34 Knock Sensor
35 EGR Temp
36 EGRC-BPT Valve
37 Closed Loop
41 IAT
43 TPS
65 Misfire, Cyl. 4
66 Misfire, Cyl. 3
67 Misfire, Cyl. 2
68 Misfire, Cyl. 1
71 Misfire, Random
72 Catalyst System
76 Fuel Injection System
77 Secondary O2 (rear)
82 Crank Position
84 A/T Diagnostics Link
95 Crank P/S Cog
98 Coolant Temp
103 A/T Park/Neutral Switch
105 EGRC Solenoid Valve
111 Inhibitor Switch
112 Vehicle Speed Sensor, A/T
113 A/T 1st Gear Signal
114 A/T 2nd Gear Signal
115 A/T 3rd Gear Signal
116 A/T 4th Gear / TCC Signal
118 Shift Solenoid Valve A
121 Shift Solenoid Valve B
123 Overrun Clutch
124 Torque Convertor Clutch
125 Line Pressure Solenoid Valve
126 TPS, A/T
127 Engine Speed Signal
128 A/T Fluid Temp Sensor
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